On the topic of tourism in Charleston, the attention often centers on out-of-town guests: what attracts them, where they're coming from and how much they're willing to spend.

But there's a small, yet significant group driving the hospitality industry that's rarely mentioned.

Local tourists, while they may sound like an oxymoron, are valuable to well-known attractions such as the S.C. Aquarium and Patriots Point Naval and Maritime Museum.

Locals who patronize those places not only boost ticket sales, they're more likely to buy year-round memberships or donate to the attractions' causes. As some of Charleston's tourism businesses head into their next financial year - many nonprofits and state agencies start their fiscal year in July - they're considering how to bring more residents through the door, and how to keep them visiting for years to come.

Local power

While it's hard to determine the exact number of locals who visit tourist sites each year, locals do make up a significant amount of attendance at some of the largest attractions in the area each year.

At Patriots Point in Mount Pleasant, about 15 percent to 20 percent of annual attendees live in the tri-county area, said Mac Burdette, executive director.

From April 2013 to January 2014, more than 321,000 visitors went to the aquarium. Of those, at least 16 percent were locals who weren't members. Membership holders, a mix of locals and out-of-towners, accounted for another 27 percent.

The aquarium has one of the largest membership bases of all the attractions in the area, with about 8,000 members, according to Kevin Mills, president and chief executive officer.

Charlotte Zacharkiw, a Charleston resident, has a family membership to the aquarium. She said she or her nanny takes her two small children to the Concord Street attraction at least once a week.

"We love it. My son loves the fish and the turtle, and it's just very easy to get around and to park," she said. "If my parents are in town, they can take the children and give me a break, and the whole family can enjoy it. We'll probably be members for a long time."

In the colder months, the local customer base is particularly important to tourist attractions.

For example, Patriots Point hosts a "Pay-What-You-Can" day in January each year to increase awareness in the community about the museum and to boost attendance during one of the slowest months.

Beyond the bucks

Ticket sales are important, but local visitors are valuable to tourism for other reasons.

For one, they often advise out-of-town guests or family members on which activities they should experience while in Charleston.

"Local residents do play a big role in helping attract visitors to the Charleston area, and they also influence what visitors see and do while they are here through their personal recommendations," said Perrin Lawson, deputy director of the Charleston Area Convention and Visitors Bureau.

Tracey Todd, chief operating officer of Middleton Place, said the local audience, particularly the 2,000 who have memberships to the Ashley River Road attraction, supports the historic site in a variety of ways.

"Our membership program is vital because they're locals, and they're constantly bringing out friends and family, sometimes out-of-town guests, and they're acquainting them with Middleton Place," he said.

Todd added that members often help with fundraising efforts and help Middleton Place build meaningful relationships in the community.

The aquarium, a nonprofit that focuses on marine conservation in the Lowcountry, relies on its local audience for the same reasons.

"They're ambassadors of our programs and our vision, which is to lead the way to connect people with wildlife, and our local audience is integral to that," said Beth Nathan, assistant director of marketing.

Challenges ahead

Patriots Point and the S.C. Aquarium, the two largest tourist attractions in the Lowcountry, are grappling with how to increase local attendance as they plan marketing strategies for their upcoming financial years.

At the aquarium, local attendance dropped by more than 40 percent from January 2013 to January this year. Membership attendance dropped by 20 percent over the same period. While tourist attendance increased by 20 percent in that time, the drop in local attendance was the most drastic dip the aquarium had seen in six years.

Part of the reason, says aquarium creative director Kevin Kampwerth, is that there weren't any new exhibits introduced in the last year.

"We had a steady turnaround of new exhibits since 2010, and we had seen a steady increase in our local market, which is great," he said in a May 7 aquarium board meeting. "This is the year we didn't have anything large, new or wild. We did start to see a dip in the membership and local attendance this year, so really our big question for marketing this year is how do we reach back out to the local audiences?"

Burdette said Patriots Point has faced similar challenges with its local attendance. "We struggle with the question each year when we're putting together our marketing plan. When we ask (locals), 'Why haven't you come back?' they'll say, 'Well, nothing's really changed.' So you've got to give people a reason to come over on a regular basis."

Specializing

One way most attractions have engaged the local community is with special events.

"We recently had a living history day when we had 150 re-enactors of Nathanael Greene's army," said Middleton's Todd. "I know we had a large local audience there. It's tremendously helpful from an exposure standpoint."

The aquarium recently had record success with locals when it hosted Florida's Weeki Wachee Mermaids, underwater entertainers who performed in the Great Ocean Tank for nine days during most public schools' spring break.

"Projects like the mermaids really resonate with (locals)," said Mills, the CEO. "We are responding to what our local public wants to experience."

The aquarium is rolling out a six-year plan called the "Watershed Fund" to improve offerings, including the visitor experience for its target audience, primarily young families with children. Part of that project is to introduce a new exhibit, Shark Shallows, which will be constructed starting in September facing the Cooper River.

Patriots Point has found success engaging locals with events such as Paws at the Point last month, when guests were encouraged to bring their pets.

The museum has broken ground on its "Vietnam Experience," an expansion of a landside exhibit that will incorporate interactive features and realistic jungle landscaping.

"The bigger things, like the Vietnam Experience, that's something we really think will resonate with locals," Burdette said. "There are a lot of Vietnam veterans who live in the tri-county area."